Photographic sensitizing dyes containing a bridgehead nitrogen

ABSTRACT

Cyanine and merocyanine photographic sensitizing dyes containing a bridgehead nitrogen atom are provided. These dyes include those represented by the formulas   WHEREIN M, N, P AND X EACH HAS A VALUE OF 0 OR 1, R AND Q EACH HAVE A VALUE OF 0, 1, 2 OR 3, L is a methine group, Z represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing 5 to 6 atoms in the heterocyclic ring, R1 represents a lower alkyl group or an aryl group, A represents an anion and Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing 5 or 6 atoms in the heterocyclic ring. Light sensitive silver halide emulsions containing such dyes are also provided.

United States Patent Fumia, Jr.

[ PHOTOGRAPHIC SENSITIZING DYES CONTAINING A BRIDGEHEAD NITROGEN OTHERPUBLICATIONS Hamer The Cyanine Dyes and Related Compounds 75 l ArthurFumia Jr" Hihan NY. pp. 275 to 277. lnterscience Publishers, a JohnWiley and Sons Division (N.Yv), l964. [731 Asslgneei Eastman KodakCmnpany- Chemical Abstracts, Vol. 68, Abstract NO. 38645d RGChesteri([968), (abst. of Meyers et ale) [22 d; Man 20 1973 Eastman KodakResearch Disclosure, Sept. 1972 pages 52 to 54. [2l] Appl. No.: 343,062

Related U.S. Application Data Primary Examiner-John D. Randolph [62]Division of SCI No. 234.389, March 13, 1972. Pat. 8 Firm-M chlpaloskl[57] ABSTRACT [52] U.S. Cl. 260/2404; 96/132; 96/l33; Cyanine andmerocyanine photographic sensitizing 96/l35; 96/136; 96/l4l; 260/2406;dyes containing a bridgehead nitrogen atom are pro- 260/240.65; 260/283SY; 260/286 R; vided. These dyes include those represented by the260/289 R; 260/296 T; 260/297 T; 260/3265 formulas CH (EH (-CH -C|ZH 2 CCH 2 CH 0 I Z t X a e CH (CH -CH(CH -C=CH(-L=CH-) C=(CH-CH=) N -R A and,cH (-ci1 -pH /CH 2 I 1 1 CH (-CH -CH(-CH2) -L(=CH-L-) C 0:0

{5 l] Int. Cl C09b 23/10 wherein m, n, p and 1' each has a value of 0 orI, r and [58] Field of Search .1 260/2404, 240.6, 24065. q each have avalue of 0, l, 2 or 3. L is a methine 260/2407; 96/l29, l3l, I32, [35group, Z represents the nonmetallic atoms necessary to complete aheterocyclic nucleus containing 5 to 6 [56] References Cited atoms inthe heterocyclic ring, R, represents a lower UMTED STATES PATENTS alkylgroup or an aryl group, A represents an anion $384,486 5/1968 Tuber etaL 260/2404 x and Q represents the nonmetallic atoms necessary to3.384.489 5/l968 Lincoln Bit! 260/2404 x Complete a hetewwchs nucleusCvmammg 5 0f 6 3.397.981 8/[968 Lincoln BI. ul zen 240.4 x atoms thehetflrocycllc s 3403-026 90968 i 260/2404 X Light sensitive silverhalide emulsions containing such 3 408.l95 l0/l968 011m 96/136 x dyesare also provided 3 557.l00 l/l97l Frced et it] 1. 260/240 R 3.772034ll/l973 Fumia .1 96/136 3,772.278 ll/l973 Jcffrcys et ul 260/2404 7Claims, N0 Drawings PHOTOGRA PHIC SENSITIZING DYES CONTAINING ABRIDGEI-IEAD NITROGEN This is a division of application Ser. No.234,389,

filed Mer. I3. 1972 now U.S. Pat. No. 3.772.034 5 the benzoxazole series(e.g.. benzoxazole, 5-

This invention relates to photographic sensitizing ehlorobenzoxazole,S-phenylbenzoxazole, 5- dyes and. more particularly, to cyanine andmerocyumetl'ylhenzoxazole. o-methylbenzoxazole. 5.6-dimenine dyes whichare useful in the preparation of photothylbenzoxazole,4.6-dimethylbenzoxazole. 5- graphiesilver halide emulsions.methoxybenzoxazole, G-methoxybenzoxazole. 5 -eth- Certain dyes of thecyanine and merocyunine dye ll) oxybenzoxazole 6- hl robenzoxaz le 5-class are known to extend the sensitivity of photohydroxybenzoxazole,o-hydroxybenzoxazole, ctc.), graphic silver halide eniulsion layers. Itis an object of those of the naphthoxazole series (e.g.,oz-naphthoxazthis invention to prov de a new class of cyanine and ole,B-naphthoxazole. etc.), those of the selenazole semerocyanme dyes whichare valuable for sensitizing ries (e 4-methylselenazole.4-phenylselenazole. photographic silver halide emulsions. It is anotherob- 5 et those of the benzoselenazole series (e.g.. benzoject of thisinvention to provide photographic silver halel nuzol jhlombenzoelenazole, 5- ide emulsions containing new dyes. It isa further objectmetho ybenzo elenazole, 5-hydroxybenzo elenazole (if this invention toprovide photographic elements C( tetrahydrobenzoselenazole. etc.). thoseof the naphthotaming new photographic emuls s. selenazole series (e.g.,a-naphthoselenazole. B-nap- These and other ob ects are acconiplished bythe thoselenazole. etc.). those of the thiazoline series (e.g.. practiceof th s In ention. c ri fly. c mp thiazoline. 4-methylthiazoline. etc.),those of the 2 providing cyanme and merocyanine dyes derived fromquingline ie q inoline, 3-methylquinoline 5- enamino ketones. or alkoxyderivatives thereof conm th |qui line 7-methylquin0line 8- taining abridgehead nitrogen. These new dyes are repmethylquinoline.o-chloroquinoline. 8- resented by the following formulas: 25chloroquinoline. o methoxyquinoline, 6-

II. CH '(-CH CH(-CH -C(=CH-L-) C 0:0 wherein m. n, p and each has avalue of (J. l, 2 3; r th q in line fi-hydroxyquinoline, 8-

and q each have a vziule of 0. l or 2; L represents a methine group; Zrepresents the nonmetullic atoms necessary to complete ii heterocyclicnucleus containing from 5 to 6 atoms in the hcterocyclic ring. such as aheterocyclic nucleus of the thiazole series (e.g., thiazole,4-methylthiazole. S-methyl-thiazole. 4- phenylthiazole.S-phenylthiazole. 4.5-dimethylthiazole, 4.5'diphenylthiazole, 4-(2-thienyl )thiazole, etc. those of the benzothiazole series (e.g..benzothiazole. 4-

ehlorobenzothiazole. S-chlorobenzothiazole, 6- chlorobenzothiazole.7-chlorobenzothiazole, 4- methylbenzothiazole. S-methylbenzothiazole, 6-methylbenzothiazole. S-hromobenzothiazole. 6- bromobenzothiazole.4-phenylhenzothiazole. S phenylbenzothiazole. 4-methoxybenzothiazole, 5methoxybenzothiuzole. h-methoxyhenzothiazole. S- iodobenzothiazole.fi-iodohenzothiazole, 4-

ethoxybenzothiazole. S-ethdxybenzothiazole. tetrahydrobenzothiazole.5.b-dimethoxyhenzothiazole. 5.6- dihydroxymethylenebenzothiazole, 5-hydroxybenzothiazole. etc. those of the naphthothiazole series (e.g..a-naphthothiazole. B-nuphthothiazole, S-methoxy-B-naphthothiazolc.S-ethoxy-B- naphthothiazole, 7-methoxy a-naphthothiazole,8-methoxy-B-naphthothiazole. etc. those of thethionaphtheno-7'6'.4.5-thiazole series (e.g.. 4'-methoxythionaphtheno-T,6'. 4.5-thiazole, etc. those ofthe oxa- Zole series (e.g.,4-methyloxazole. S-methyloxazole, 4- phenyloxazole. 4.5-diphenyloxaz0le,4-ethyloxazole. 4.5-dimethyloxazole. 5-phenyloxazole. etc.), those ofhydroxyquinoline. etc.). those of the 4quinoline series (e.g..quinoline. o-methoxyquinoline, 7- methylquinoline. S-methylquinoline.etc. those of the Lisoquinoline series (e.g.. isoquinoline. 3.4-dihydroisoquinoline. etc.), those of the 3,3- dialkylindolenine series(e.g. 3.3-dimethylindolenine. 3.3.S-trimethylindolenine.3,3,7-trimethylindolenine. etc.) those of the Z-pyridine series (eg.pyridine. 3 methylpyridine, 4-methylpyridine, S-methylpyridine.

b-methylpyridine. 3.4-dimethylpyridine. 3.5- dimethylpyridine.3.6-dimethylpyridine, 4.5- dimethylpyridine. 4.6-dimethylpyridine. 4-

chloropyridine. 5chloropyridine, b-chloropyridine. 3- hydroxypyridine.4-hydroxypyridine, 5- hydroxypyridine. fi-hydroxypyridine.3-phenylpyridine. 4-phenylpyridine. o-phenylpyridine, ete). those of the4-pyridine series (e.g.. Z-methylpyridine, 3- methylpyridine.2-chloropyridine. 3-chloropyridine. 2.3-dimethylpyridine.2,5-dimethylpyridine, 2,6 dimethylpyridine. 2-hydroxypyridine, 3-hydroxypyridine. etc). those of the imidazole series (e.g., imidazole,4-methylimidazole. S-ethylimidazole. 4-chloroimidazole.4.5-dichloroimidazole. 4- methoxyimidazole. S-phenylimidazole. etc).those of the benzimidazole series (e.g.. benzimidazole. 4-methylbenzimidazole. S-methylbenzimidazole. 6-

methylbenzimidazole. 5.b-dichlorobenzimidazole. 5- chlorobenzimidazole.S-phenylbenzimidazole. 6- phenylbenzimidazole. etc.). those of thenaphthimidazole series (e.g.. a-naphthimidazole. B-naphthimidazole.etc). those of the lepidine series (e.g.. lepidine. 7-chlorolepidine.7-methyllepidine. etc. R, preferably represents a lower alkyl grouphaving 1 to 8 carbon atoms such as methyl. ethyl, propyl, butyl. etc..and including substituted lower alkyl groups such as carboxyalkyl group(e.g.. carboxymethyl. carboxyethyl. carboxypropyl. carboxybutyl, etc.).a carbalkoxyalkyl group (e.g.. carbomethoxymethyl. carbethoxyethyl,carbopropoxyethyl. carbopropoxybutyl. etc.). a sulfoalkyl group (e.g..sulfomethyl. sulfoethyl. sulfopropyl. sulfobutyl. etc.), a hydroxyalkylgroup (e.g.. hydroxymethyl, hydroxyethyl. hydroxypropyl. hydroxybutyl.etc.). and alkoxyalkyl group (e.g.. methoxyethyl. methoxypropyl,ethoxyethyl. ethoxypropyl etc.), a sulfoalkoxyalkyl group. as well as anaryl group such as phenyl. 4-methylphenyl. 4-chlorophenyl. etc.; Arepresents an anion such as chloride. bromide. iodide.p-toluenesulfonate. thiocyanate, perchlorate. acetate. methylsulfate.ethylsulfate. etc.; represents the nonmetallic atoms necessary tocomplete a heterocyclic nucleus containing or 6 atoms in theheterocyclic ring, such as heterocyclic nucleus of the Z-pyrazolin-S-one series (e.g.. 3-methyl-l-phenyl-Z-pyrazolin- S-one, 3ethyl-1-phenyl-2-pyrazolin-5-one. 3-phenyl-lmethyLZ-pyrazolin-S-one.etc), a heterocyclic nucleus of the indandione series (e.g.. l3-diketohydrindene. etc.). those of the2,4.fi-triketohexahydropyrimidine or2.6-diketo-4-thiohexahydropyrimidine series (e.g., barbituric acid orZ-thiobarbituric acid) as well as their 1- alkyl (e.g.. l-methyl.l-ethyl, l-n-propyl. l-n-heptyl. etc). or l.3-dialkyl (e.g..l,3-dimethyl, l,3-diethyl, l,3-di n-propyl, 1.3-dicyclohexyl, etc.) orl.3-diaryl (e.g.. L3-diphenyl. l,3-di(p-chlorophenyl). etc.). or l-aryl(e.g.. l-phenyl. l-p-chlorophenyl. l-p-ethoxycarbonylphenyl. etc). orl-alkyl-3-aryl (e.g., l-ethyl- El-phenyl l-n-heptyl-3-phenyl. etc.)derivatives, etc.; a heterocyclic nucleus of the rhodanine series (e.g..rhodanine. 3-ethylrhodanine, 3-propylrhodanine. 3' butylrhodanine.3-(p-carboxyphenyl)rhodanine. 3-(p-sulfophenyl)rhodanine. etc.). aheterocyclic nucleus of the hydantoin series (e.g., hydantoin,l-(pcarboxyphenyl)-3-phenylhydantoin. l-ethyl-3- phenylhydantoin. etc.).a heterocyclic nucleus of the thiohydantoin series (eg, Z-thiohydantoin.lpcarboxyphenyl-3-phenyl 2-thiohydantoin. l-psulfophenyl-3-phenyl-Z-thiohydantoin. l-ethyl-3- phenyl-Z-thiohydantoin,etc). a heterocyclic nucleus of the 2-thio-2.4-oxazolidinedione series(e.g.. 2-thio- 2.4-oxazolidinedione, 3-(p-sulfophenyl)-2-thio-2,4-oxazolidinedione. 3-ethyl-2-thio-2.4-oxazolidinedione.

etc.

Compounds l and II can be prepared from enamino ketones. or etherderivatives thereof. containing bridgehead nitrogen. Such intermediatescan be represented by the formulas on (4:11,) -ca r i ca N cydrocyclopenta[c]quinolizin-4-one (m.p. 6768C.) having the formula I llca (-ca -CH(-Cll -C-OR can be prepared by heating ethylZ-piperidylacetate and cyclopentanone according to the procedure de'scribed by Myer et al, J. Heterocyclic Chemistry. Vol.

5. pages l5ll59 (I968). In a similar manner, the compound2,3.4.4a.5,6,7.8.9,lO-decahydro-1Hbenzo[c]quinolizin-6-one (m.p. 7778C.C.) having the formula jgo can be prepared by heating ethyl3-piperidylacetate and cyclohexanone; and13,311.45.6.7.8-octahydrolH-cyclopenta[e]-indolizin-5-one (m.p. 97-98C.)having the formula can be prepared by condensingethyl-2-pyrrolidinylacetate and its acetate salt with cyclopentanone.Ethyl-2-pyrrolidinylacetate and its acetate salt can be prepared by thehydrogenation of ethyl-2-pyrrolylacetate having the formula according tothe procedure described by Adams et al. .l.A.C.S.. Vol. 83. page 3323(l96l). The compound can be pared by condensing cyclopentanone withethyl- 2-pyrrolidinyl formate.

The intermediates of Compound IV can be prepared by heating a mixture ofa compound of Compound ill and triethyloxonium fluoborate in an inertsolvent. Thus, 4-ethoxy-2.3.S.5a.6.7.8.9-octahydro-1H- cyclopentalclquinolizinium fluoborate.

can be prepared as follows:

1.2.3 .4.5u.6.7.8 .9-Decahydrocyclopenta[c lquinolizin-4-one (9.55 g.)and triethyloxonium fluoborate (9.50 g.) are dissolved indichloromethane (l ml.) and heated at reflux for IS minutes. Afterchilling. the mixture is diluted to about 400 ml. with ether and chilledfurther. The solid product is then collected on a filter and dried in avacuum oven at 60 C. to yield 14.87 g. (97%). mp. 63-65C.

In the same manner.fi-ethoxyl.2.3.4.4a,5.6.7.8.9.lO-decahydro[clquinolizinium fluoborate.

2.3 .4.4u.5.6.7.8.9. l 0- with triecan be prepared by condensingdecahydrol Hbenzo[ c lquinolizin-o-one thyloxonium fluoborate.

The cyanine dyes of Formula I (p= 0) can be conveniently prepared byheating a mixture of a compound of Compounds III or IV with anitrogen-containing heterocyclic compound containing a reaction methylgroup having the formula 9 I R N(=CH--CH) =C--CH wherein R A. Z and areas previously defined. When the intermediate of Compound III isemployed. the reaction is preferably conducted in acetic anhydride. Whenthe intermediate of Compound IV is employed. the reaction is preferablyconducted in an inert solvent. such as pyridine. quinoline.isoquinoline. ethanol. npropanol. n-butanol. etc.. and in the presenceofa basic condensing agent such as the trialkyl amines (e.g..triethylamine. tri-n-propylamine. tri-n-butylamine. etc.).N-methylpiperidine. N-ethylpiperidine. N.N- dimethylaniline. etc.

The merocyanine dyes of Formula ll (q=0) can be conveniently prepared byheating a mixture of a compound of Compound TV with anitrogen-containing heterocyclic compound containing a reactivemethylene group having the formula VI I H 0 C=O wherein O is aspreviously defined. The reaction is preferably conducted in an inertsolvent such as pyridine. quinoline. isoquinoline. ethanol. n-propanol.nbutanol. etc. and in the presence ofa basic condensing agent such asthe trialkyl amines (e.g.. triethylamine. tri-npropylamine.tri-n-butylamine. etc. N- methylpiperidine. N-ethylpiperidine. N.N-dimethylaniline, etc.

The longer chain cyanine and merocyanine dyes can be prepared fromCompound VII below which in turn can be prepared from Compound IV by themethods disclosed in Examples 2-4 and lines 8-29. Column 4 of US. Pat.No. 3.440.052. Compound VII can be converted to Compound Vlll below bymethods well known in the art utilizing. for example.diphenylformamidine. B-anilinoacrolein. anil hydrochloride, orglutaconaldehyde dianil hydrochloride. Dyes of the invention can then beprepared by reacting Compound Vlll with Compound V or Compound Vl.Symmetrical cyanine dyes can also be made by reacting Compound Vll withsuch compounds as ethyl orthoformate. ethylorthopropionate.trimethoxypropene or glutaconaldehyde dianil hydrochloride.

wherein s is an integer of l to 3'. R is an alkyl or an aryl group and Ris an aryl group.

Typical longer chain cyanine and merocyanine dyes include:

2-[3-(2.3.4.4a.5.6.7.8.9.lO-Decahydro lH-benzo[elquinolizin-o-ylidene)propenyll-3-ethylbenzoxazolium iodide2-[5-(2.3.4,4a.5.6.7.8.9.l0-Decahydro-lHbenzole]quinolizin-6-ylidene)-I.3-pentadienyl]-3- ethyl benzothiazoliumiodide 5-[2.3.4.4a.5.6.7,8.9.lO-Dccahydro-1H-benzolelquinolizin-o-ylidene)ethylidene1-3- ethylrhodanine(1.2.3.4.4a.5.7.8.9. l0-Decahydrobenzol e quinolizino)carbocyanineiodide.

The alkyl groups or moieties referred to herein typically have 1 to 20carbon atoms. lower alkyl radicals or moieties have 1 to 8 carbon atomsand aryl groups or moieties typically include phenyl and naphthyl.

The new dyes of this invention are excellent spectral and chemicalsensitizers for photographic silver halide emulsions and particularlyfor negative silver halide systems. The silver halide emulsions whichcan be spectrally sensitized by the dyes of this invention can comprise.for example. silver chloride. silver bromide. silver bromoiodide. silverchlorobromide. silver chloroiodide. silver chlorobromoiodide crystals ormixtures thereof. The emulsions can be coarse or fine grain emulsionsand can be prepared by a variety of techniques. e.g.. single jetemulsions such as those described in Trivelli and Smith. ThePhotographic Journal. Vol. LXXIX. May I939 (PP- 330-338). double jetemulsions such as Lippmann emulsions. ammoniacal emulsions. thiocyanateor thioether ripened emulsions such as those described in Neitz et al.U.S. Pat. No. 2.222.264 issued Nov. l9. I940; Illingsworth U.S. Pat. No.3.320.069 issued May l7. I967 and McBride U.S. Pat. No. 3.27l.l57 issuedSept. 6. I966. Silver halide emulsions can form latent imagespredominantly on the surface of the silver halide grains. orpredominantly on the interior of the silver halide grains such as thosedescribed in Davey et al. US. Pat. No. 2.592.250 issued May 8. I952;Porter et al. U.S. Pat. No. 3.206.3l3 issued Sept. l4. I965; BerrimanU.S. Pat. No. 3.367.778 issued Feb. 6. I968 and Bacon et al. U.S. Pat.No. 3.447.927 issued June 3. I969. If desired, mixtures of such surfaceand internal image-forming emulsions can be made. such being describedin Luckey et al. U.S. Pat. No. 2.996.382 issued Aug. 15. I961. Silverhalide emulsions can be regular grain emulsions such as the typedescribed in Klein and Moisar. J. P1101. Sci.. Vol 12. No. 5.Sept./Oct.. I964. pp. 242l. Negative type emulsions can be made. as wellas direct positive emulsions as described in Leermakcrs U.S. Pat. No.2.I 84.0 I 3 issued Dec. I9. I939; Kendall et al. U.S. Pat. No.2.541.472 issued Feb. 13. I95I; Schouwenaars British Pat. No. 723.019issued Feb. 2. I955; lllingsworth et al. French Pat. No. 1.520.821issued Mar. 4. I968; lllingsworth US. Pat. No. 3.50l .307 issued Mar.I7. 1970; lves U.S. Pat. No. 2.563.785 issued Aug. 7. I95]; Knott et al.U.S. Pat. No. 2.456.953 issued Dec. 21. I948 and Land U.S. Pat. No.2.86] .885 issued Nov. 25. I958.

The silver halide emulsions can be unwashed or washed to remove solublesalts after precipitation of the silver halide. In the latter case. thesoluble salts can be removed by chill-setting and leaching or the emulsion can be coagulation washed. e.g.. by the procedures described inHewitson et al. U.S. Pat. No. 2.6l8.556 issued Nov. I8. I952; Yutzy etal. U.S. Pat. No. 2.614.928 issued Oct. 2|. I952; Yackel U.S. Pat. No.2.565.4I8 issued Aug. 2|. 195]; Hart et al. U.S. Pat. No. 3.24I.969issued Mar. 22. 1966 and Waller et al. U.S. Pat. No. 2.489.34l issuedNov. 29. I949.

The dyes of this invention are advantageously incorporated in thewashed. finished emulsion and should be uniformly distributed throughoutthe emulsion. The dyes can be added from solutions in appropriatesolvents which are compatible with the emulsion and which aresubstantially free from deleterious effects on the light sensitivematerials.

The types of silver halide emulsions that can be sensitized with the newdyes of this invention include those prepared with hydrophilic colloidsthat are known to be satisfactory vehicles for dispersed silver halides.for example. emulsions comprising both naturally occurring substancessuch as proteins. for example. gelatin. gela tin derivatives. cellulosederivatives. polysaccharides such as dextran. gum arabic and the like;and synthetic polymeric substances such as water soluble polyvinylcompounds like poly-(vinylpyrrolidone). acrylamide polymers and thelike. The photographic emulsions can also contain along or incombination with hydrophilic. water-permeable colloids. other syntheticpolymeric vehicle compounds such as dispersed vinyl compounds such as inlatex form and particularly those which increase the dimensionalstability of the photographic materials. Typical synthetic polymersinclude those described in Nottorf U.S. Pat. No. 3.I42.568 issued July28. I964; White U.S. Pat. No. 3.I93.386 issued July 6. I965; Houck etal.. U.S. Pat. No. 3.062.674 issued Nov. 6. I962; Houch et al. U.S. Pat.No. 3.220.844 issued Nov. 30. I965; Ream et al. U.S. Pat. No. 3.287.289issued Nov. 22. I966; and Dykstra U.S. Pat. No. 3.4I I.9ll issued Nov.I9. 1968. Other vehicle materials include water-insoluble polymers ofalkyl acrylates and methacrylates. acrylic acid. sulfoalkyl acrylates ormethacrylates. those which have cross-linking sites which facilitatehardening or curing as described in Smith U.S. Pat. No. 3.488.708 issuedJan. 6. I970. and those having recurring sulfobetaine units as describedin Dykstra Canadian Pat. No. 774.054.

The concentration of the new dyes in the emulsion can vary widely. tag.from about 25 to l.00() mg. per mole 'of silver halide in the emulsion.The specific concentration will vary according to the type oflightsensitive material in the emulsion and the effects desired. Thesuitable and most economical concentration for a given emulsion will beapparent to those skilled in the art upon making the test andobservations customarily used in the art of emulsion making.

To prepare a gelatin-silver halide emulsion sensitized with one of thedyes of this invention. the following procedure is satisfactory. Aquantity of the dye is dis solved in a suitable solvent and a volume ofthis solution containing from 25 to 1.000 mg. of dye is slowly added toone mole of silver halide in a gelatin-silver halide emulsion. With mostof the dyes. I00 to 300 mg. of dye per mole of silver halide suffices toproduce the maximum sensitizing effect with the ordinary gelatin silverbromide (including bromoiodide and chlorobromide) emulsions. With finegrain emulsions. which include most of the ordinarily employedgelatin-silver chloride emulsions. somewhat larger concentrations of dyemay be necessary to obtain the optimum sensitizing effect. While thisprocedure has dealt with emulsions comprising gelatin. it will beappreciated that these remarks apply generally to any emulsion whereinall or part of the gelatin is substituted by another suitablehydrophilic colloid as mentioned above.

Photographic silver halide emulsions containing the sensitizing dyes ofthis invention can also contain other addenda such as chemicalsensitizers. e.g.. reducing agents; sulfur..selenium or telluriumcompounds; gold. platinum or palladium compounds; or combinations ofthese. Procedures for chemically sensitizing silver halide emulsions aredescribed in Sheppard et al. U.S. Pat. No. I.623.499 issued Apr. 5.I927; Waller et al. U.S. Pat. No. 2.399.083 issued Apr. 23. I946;McVeigh U.S. Pat. No. 3.297.477 issued .lan. I0. 1967 and Dunn US. Pat.No. 3.297.446 issued Jan. I0. I967. The emulsions can containdevelopment modifiers that function as speed increasing compounds suchas polyalkylene glycols. cationic surface active agents and thioethersor combinations of these as described in Piper U.S. Pat. No. 2.866.437issued May I2. I959; Dann et al. U.S. Pat. No. 3.046.900 issued July I2.1960 and Goffe U.S. Pat. No. 3.294.540 issued Dec. 27. 1966.

The silver halide emulsions can be protected against the production offog and can be stabilized against loss of sensitivity during keeping.Useful antifoggants and stabilizers. each used alone. or in combination.include: (a) thiazolium salts described in Brooker et al. U.S. Pat. No.2.131.038 issued Sept. 27. 1938 and Allen et al. U.S. Pat. No. 2.694.716issued Nov. 16. 1954; (b) the azaindenes described in Piper U.S. Pat.No. 2,886,437 issued May 12. 1959 and Heimbach et al. U.S. Pat. No.2,444,605 issued July 6. 1948; (c) the mercury salts as described inAllen et a1. U.S. Pat. No. 2.728.663 issued Dec. 27. 1955; (d) theurazoles described in Anderson et al. U.S. Pat. No. 3.287.135 issuedNov. 22. 1966'. (e) the sulfocatechols described in Kennard et al. U.S.Pat. No. 3.236.652 issued Feb. 22. 1966; (f) the oximes described inCarrol et a1. British Pat. No. 623.448 issued May 18. 1949; (g) nitron;(h) nitroindazoles; (i) the mercaptotetrazoles described in Kendall etal. US. Pat. No. 2.403.927 issued July 16. 1946; Kennard et al. U.S.Pat. No. 3.266.897 issued Aug. 16. 1966; and Luckey et a1. U.S. Pat. No.3.397.987 issued Aug. 20. 1968'. (j) the polyvalent metal saltsdescribed in Jones U.S. Pat. No. 2.839.405 issued june 17. 1958; (k) thethiuronium salts described in Herz et al. U.S. Pat. No. 3.220.839 issuedNov. 30. 1965; and (l) the palladium. platinum and gold salts describedin Trivelli et a1. U.S. Pat. No. 2.566.263 issued Aug. 28. 1951'. andYutzy et al. U.S. Pat. No. 2.597.915 issued May 27. 1952.

The photographic silver halide emulsions of this in vention can becoated on a wide variety of supports. Typical supports include cellulosenitrate film. cellulose acetate film. poly(vinyl acetal) film.polystyrene film. poly(ethylene terephthalate) film. polycarbonate filmand related films or resinous materials. as well as glass. paper. metaland the like. Typically. a flexible support is employed. especially apaper support. which can be partially acetylated or coated with barytaand/or an alpha-olefin polymer. particularly a polymer of analpha-olefin containing 2 to 10 carbon atoms such as polyethylene.polypropylene. ethylenebutene copolymers and the like.

Photographic elements having silver halide emulsions coated thereon cancontain developing agents such as hydroquinones. catechols.aminophenols. 3- pyrazolidones. ascorbic acid and its derivatives.reductones and phenylenediamines. Combinations of developing agents canalso be employed. The developing agents can be in a silver halideemulsion and/or in another suitable location in the photographicelement. The developing agents can be added from suitable solvents or inthe form of dispersions as described in Yackel U.S. Pat. No. 2.592.368issued Apr. 8. 1952 and Dunn et al. French Pat. No. 1.505.778. Theemulsion layers can be hardened by various organic or inorganichardeners. alone or in combination. such as those disclosed in Mees andJames. The Theory ufrhe Photographic Process pp. 54-60. 3rd Ed.MacMillan. Typical useful hardeners include the aldehydes. and blockedaldehydes as described in Allen et a1. U.S. Pat. No. 2.232.764 issuedFeb. 1. 1966; ketones. carboxylic and carbonic acid derivatives.sulfonate esters. sulfonyl halides; vinyl sulfonyl esters as describedin Burness et a1. U.S. Pat. No. 2.539.644 issued Nov. 10. 1970; activehalogen compounds; epoxy compounds; aziridines'. active olefins;isocyanates; carbodiimides; chlorotriazines as disclosed in Yamamoto etal. U.S. Pat. No.

3.325.287 issued June 13. 1967; Oishi et al. U.S. Pat. No. 3.362.827issued Jan. 9. 1968. Nishio et al. U.S. Pat. No. 3.394.006 issued July23. 1968 and Meckl et al. U.S. Pat. No. 3.549.377 issued Dec. 22. 1970;polymeric hardeners such as oxidized polysaccharides like dialdehydestarch and oxyguargum; and the like.

The layers present in photographic elements made according to thisinvention may also contain colorforming couplers such as those describedby Schneider. Frolich and Schultze. Die Chemie 57. l 13 (1944); inFrolich et al. U.S. Pat. No. 2.376.679 issued May 22. 1945; Jelley eta1. U.S. Pat. No. 2.322.027 issued June 15. 1943; Salminen et al. U.S.Pat. No. 2.423.730 issued July 8. 1947'. Weissberger et al. U.S. Pat.No. 2.474.293 issued June 28. 1949; Loria et a1. U.S. Pat. No. 2.600.788issued June 17. 1952; Salminen et a1. U.S. Pat. No. 2.772.162 issuedNov. 27. 1956; Fierke et al. U.S. Pat. No. 2.801.171 issued July 30.1957'. Godowsky U.S. Pat. No. 2.698.794 issued Jan. 4. 1955; McCrossenet a1. U.S. Pat. No. 2.875.057 issued Feb. 24. 1959; Salminen et al.U.S. Pat. No. 2.895.826 issued July 21. 1959; Bush et al. U.S. Pat. No.2.908.573 issued Oct. 13. 1959; Beavers U.S. Pat. No. 2.983.608 issuedMay 9. 1961; Gledhill et a1. U.S. Pat. No. 3.034.892 issued May 15.1962; Barr et al. U.S. Pat. No. 3.227.554 issued Jan. 4. 1966;Weissberger et a1. U.S. Pat. No. 3.062.653 issued Nov. 6. 1962'.Weissberger et al. U.S. Pat. No. 3.265.506 issued Aug. 9. 1966; LoriaU.S. Pat. No. 3.408.194 issued Oct. 29. 1968; Lestina U.S. Pat. No.3.519.429 issued July 7. 1970; Graham et a1. U.S. Pat. No. 3.046.129issued July 24. 1962'. Vittum et a1. U.S. Pat. No. 2.360.290 issued Oct.10. 1944; and Thirtle et al. U.S. Pat. No. 2.701.197 issued Feb. 1.1955.

The photographic layers of this invention may also include other addendaknown to be beneficial in photographic emulsions. Thus. they can containplasticizers and lubricants such as polyalcohols. e.g.. glycerin anddiols of the type described in Milton et a1. U.S. Pat. No. 2.960.404issued Nov. 1. 1966; fatty acids or esters such as those described inRobijns U.S. Pat. No. 2.588.765 issued Apr. 11. 1952. and Duane U.S.Pat. No. 3.121.060 issued Feb. 1 1. 1964; and silicone resins such asthose described in DuPont British Pat. No. 955,061 issued Apr. 15. 1964.

The layers can contain surfactants such as saponin; anionic compoundssuch as the alkyl aryl sulfonates described in Baldsiefen U.S. Pat. No.2.600.831 issued Jun. 17. 1952; amphoteric compounds such as thosedescribed in Ben-Ezra U.S. Pat. No. 3.133.816 issued May 10. 1964', andwater soluble adducts of glycidol and an alkyl phenol such as thosedescribed in Olin Ma thieson British Pat. No. 1.022.878 issued Mar. 16.1966; and Knox U.S. Pat. No. 2.514.293 issued May 26. 1970. Mattingagents can also be included such as starch. titanium dioxide. zincoxide. silica. polymeric beads including beads of the type described inJelley et al. U.S. Pat. No. 2.992.101 issued July 11. 1961 and Lynn U.S.Pat. No. 2.701.245 issued Feb. 1. 1955'. and alkali soluble polymericparticles of the type described in Jelley et al. U.S. Pat. No.2.992.101. The photographic elements can contain brightening agentsincluding stilbenes. triazines. oxazoles and coumarin brighteningagents. Water soluble brightening agents can be used such as thosedescribed in Albers et al. German Pat. No. 972.067 issued May 14. 1959and McFall et al.. U.S. Pat. No. 2.933.390 issued Apr. 19. 1960; ordispersions of brighteners can be used such as those described in JansenGerman Pat. No. 1.150.274 issued June 12, 1963; Oetiker et al. U.S. Pat.No. 3.406.070 issued Oct. 15. 1968'. and Heidke French Pat. No.1.530.244.

Various layers of a photographic element. including light sensitivelayers. can contain light absorbing materials and filter dyes such asthose described in Sawdey et al. U.S. Pat. No. 2.739.971 issued Mar. 27.1956; Heller et al. U.S. Pat. No. 3.004.896 issued Oct. 17. 1961; SawdeyU.S. Pat. No. 3.250.617 issued May 10. 1966; Sawdey U.S. Pat. No.3.253.921 issued May 31. 1966; Gaspar US. Pat. No. 2.274.782 issued Mar.3. 1942; Silberstein et al. U.S. Pat. No. 2.527.583 issued Oct. 31,1950; and VanCampen U.S. Pat. No. 2.956.879 issued Oct. 18, 1960. Ifdesired. the dyes can be mordanted, for example. as described in Joneset al. U.S. Pat. No. 3.282.699 issued Nov. 1, 1966.

The following examples illustrates the best modes contemplated forcarrying out this invention.

EXAMPLE l 3-Ethyl-2-( l.2.3.4.5.5a6.7.8.9-decahydrocyclopenta-[c)quinolizin-4-ylidenemethyl)benzothiazolium iodidel.2.3.4.5.5u.6.7.8.9-Decahydrocyclopenta[clquinolizin-4-one (1.91 g.)and 3-ethyl-2-methylbenzothiazolium iodide (3.05 g.) are dissolved inacetic anhydride (15.0 ml.) and heated at reflux for 2 minutes. Afterchilling, the crude dye is collected on a filter. After onerecrystallization from methanol, the yield of purified dye is 1.49 g.(31% yield). m.p. 296297C. (dec.).

EXAMPLE 2 l-Ethyl-2-( l 2.3.4.5.5u.6.7.8.9-decahydrocyclopenta- [clquinolizin-4-ylidenemethyl)naphthol 1,2-

dlthiazolium iodide 45 EXAMPLE 3 Decahydrocyclopental c]quinolizin-4-ylidenemethyl 3-ethyl-5-methoxybenzothiazolium perchlorate3-Ethyl-5-methoxy-Z-methylbenzothiazolium p-toluenesulfonate (3.79 g.).l.2.3.4.5.5a,6.7.8.9- decahydrocyclopentalc]quinolizin-4-one (1.91 g.)and sodium perchlorate (1.5 g.) are dissolved in acetic anhydride (30ml.) and heated at reflux for 5 minutes. After chilling. the crude dyeis collected on a filter. After one recrystallization from methanol. theyield ol purified dye is 0.97 g. (20% yield). m.p. 244-245C.(- dec.).

EXAMPLE 4 5-( l .2.3.4.5.5u.6.7.8.9-Decahydrocyclopentalc]-quinolizin-4-ylidene )-3-ethylrhodanine4-Ehoxy-2.3.5.5a.6.7.8.9-octahydrol H- cyclopentalcl-quinoliziniumfluoborate (3.07 g.). 3- ethylrhodanine (1.61 g.) and triethylamine (1.5ml.) are dissolved in ethanol (15 ml.) and heated at reflux for 5minutes. After chilling. the crude dye is collected on a filter. Afterone recrystallization from ethanol. the yield of purified dye is 1.98 g.(59% yield), m.p. l53-l54C. (dec.).

EXAMPLE 5 4-( l.2.3,4.5.5u,6,7.89.-Decahydrocyclopenta[c]-quinolizin-4-ylidene )-3-methyll -phenyl-2-pyrazolin S-one4-Ethoxy-2.3.4.5.5a.6.7.8.9-octahydrol H- cyclopentalc]quinoliziniumfluoborate (1.54 g.). 3- methyl-1-phenyl-Z-pyrazolin-S-one (0.87 g.) andtri ethylamine (1.0 ml.) are dissolved in ethanol (10 ml.) and heated atreflux for 5 minutes. After chilling. the crude dye is collected on afilter. After one recrystallization from methanol. the yield of purifieddye is 0.76 g. (44% yield). m.p. 218-219C. (dec.).

' EXAMPLE 6 3Ethyl-2-( 23.30.45 ,6.7,8-octahydrol H-cyclopentalelindolizin-5-ylidenemethyl)benzothiazolium iodide 2,3.3a,4.56.7.8-Octahydro-1H-cyclopenta[e]indolizin-S-one (0.89 g.) and thiazoliumiodide 1.53 g.) are dissolved in acetic anhydride ml.) and heated atreflux for 3 minutes. The solution is seeded with crystals obtained froma test tube experiment. the mixture is chilled, the crude dye iscollected on a filter and recrystallized from methanol. The dye isfurther recrystallized from ethanol. The yield is 0.15 g. (6% yield).m.p. 304-305C. (dec.).

EXAMPLE 7 3-Ethyl-5 2,3 ,3a.4 5,6.7 .8-oetahydro-l H-cyclopenta- [elindolizin-S-ylidene )rhodanine NC l-l S S To a solution of23,311.45.6.7,8-octahydro-1H- cyclopentalelindolizin-S-one (1.49 g.) indichloromethane (5 ml.) is added triethyloxonium fluoborate (1.60 g.).and the mixture is heated at reflux for minutes. After cooling, themixture is diluted twice with 100 ml. portions of ether and decanted.The oily residue is dissolved in ethanol (5 ml.). 3- ethylrhodanine(1.29 g.) and triethylamine (1.0 ml.) are added and the mixture isheated at reflux for 10 minutes. After chilling. the crude dye iscollected on a filter and recrystallized once from ethanol. The yield is1.13 g. (44% yield), m.p. 225226C. (dec.).

EXAMPLE 8 2-( 2.3.4,4u,5 .6 7,8,9.10-Decahydro-lH-benzo[c]-quinolizin-o-ylidenemethyl)-3-ethylnaphtho[ 2,3-d1- thiazoliumfluoborate l c n BF 3-Ethyl-2-methylnaphthol 2.3-d lthiazoliump-toluenesulfonate (3.99 g. o-ethoxy- 1.2.3 ,4,4a,5,7 8.9. l0-decahydrobenzo[ c I- 3-ethyl-2-methylbenzo- 1 14 methanol. the yieldof purified dye is 0.30 g. (6% yield). m.p. above 310C.

EXAMPLE 9l-Ethyl-2-(2,3,30,45,6.7.8-octahydro-1H-eyclopentale]indolizin-S-ylidenemethyl)naphthol 1,2- d]thiazolium iodide S CH4. l

I- Z S EXAM PLE 10 3-Ethyl-2-(13,311.45,6.7.8-octahydro-l Hcyclopenta[elindolizin-0b S-ylidenemethyl )benzoselenazolium perchlorateSe CH- l C10 C H 23,311.45,6.7,8 Octahydro-l H-cyclopenta[eindolizin-S-one (0.89 g.) and 3-ethyl-2- methylbenzoselenazoliump-toluene-sulfonate are dissolved in acetic anhydride 15 ml.) and heatedat reflux for 3 minutes. The reaction mixture is treated with l g. ofsodium perchlorate in about 2 m1. of water and chilled. The crude dye iscollected on a filter. After one recrystallization from methanol,followed by a water wash and then an ether wash, the yield of purifieddye is 0.18 g. (7% yield). m.p. above 320C.

EXAM PLE l l 2-( l .2,3.4,5,5a,6,7,8,9-Decahydrocyclopentale]-quinolizin-4-ylidenemethyl)-3-ethylbenzoselenazolium iodide Se CH N I lC l-I 1.2.3.4.5 .5a.6.7,8.9-Decahydrocyclopentalc- ]quinolizin-4-one(1.91 g.) and 3-ethyl-2- qulnolillnium fluobol'ilte (3-2] 8- imd"ielhylamine methylbenzoselenazolium p-toluenesulfonate (3.84

(1.5 ml.) are dissolved in ethanol (15 ml.) and heated at reflux for 5minutes. After chilling, the crude dye is collected on a filter. Afterone recrystallization from g.) are dissolved in acetic anhydride (15ml.) and heated at reflux for 2 minutes. The reaction mixture is treatedwith 2 g. of sodium iodide in about 5 ml. of

water and. after chilling, the crude dye is collected on a filter. Afterone recrystallization from methanol. fol' lowed by a water wash and thanan ether wash. the yield of purified dye is 0.73 g. (l4 7r yield). m.p.302303C. (dec.).

EXAMPLE 1?.

5-(12.3.4.551.6.7.8.O-Decahydroeyclopenta[elquinolizin4'ylidene )-3-I3-( 3-pyrrolin-l -yl)propyl rhodanine N-(Cil N St S S4-Ethoxy-2.3.4.5.5a.6.7.8.9-octahydro 1H- cyclopentwlc]quinoliziniumfluoborate (1.54 g.). 3-

EXAMPLE l3 2-( l.2.3.4.5.5a.6.7.8.9-Decahydrocyclopentalelquinolizin-4-ylidenemethyl-Emethylthiazoliumchlorate per- en 4-Ethoxy-2.3.4.4u.6.7.8.9-octahydro-] H-cyclopentalclquinolizinium fluoborate (1.54 g.). 2.3-dimethylthiazolinium iodide (1.22 g.) and triethylamine (1.0 ml.) aredissolved in ethanol (l ml.) and heated at reflux for 4 minutes. Sodiumperchlorate 1.0 g.) is added and the solution is heated at reflux for anadditional 2 minutes. After chilling, the crude dye is collected on afilter. After one recrystallization from methanol. the yield of purifieddye is 0.52 g. (27% yield). m.p. 224-225C. (dec.).

EXAM PLE l4 2-( 2.3.4.405 ,6 .7.8.9. I O-Decahydro- H-benzol equinolizin-6-ylidenemethyl )-3-ethylbenzothiazolium c n. I

2.3.4.4u.5.6.7.8.9.lO-Deeahydro-lH-benzo[c- Iquinolizin-bone (2.05 g.)and 3-ethyl-2'methylbenzothiazolium iodide are dissolved in aceticanhydride l5 ml.) and heated at reflux for 3 minutes. After chilling.

the crude dye is collected on a filter and recrystallized once frommethanol. The yield of purified dye is 0.94 g. (19% yield). m.p.3l9320C. (dec.).

EXAMPLE l4 2( 2.3.4.4a.5.6.7.8.9. l O-Decahydro-l H-benzol equinolizin-fi-ylidene methyl -ethyln aphtho[ l.2-d thiazolium iodide Scn- I 2.3.4.4u.5.6.7.8.9. l O-Deeahydro-l H- henzolclquinolizin fi-one(2.05 g.) and l-ethyl-Z- methylnapthol l.2-d]thiazoliump-toluenesulfonate are dissolved in acetic anhydride l5 ml.) and heatedat reflux for 3 minutes. The reaction mixture is treated with aqueoussodium iodide (2 g. in about 5 ml.) and chilled. The crude dye iscollected on a filter and after one recrystallization from methanol theyield of purifled dye is 0.4] g. (8% yield). m.p. 244-245C. (dec.).

EXAMPLE [6 5-(2.3.4.4u.5.6.7.8.9. lO-Decahydro-lH-benzole1-quinolizin-o-ylidene )-3-ethylrhodanine N-CQHE Sb-Ethoxy-l.2.3.4.4a.5.6.7.8.9.lO-Decahydrobenzo(e]-quinoliziniumfluoborate (3.2l g.). 3- ethylrhodanine (1.6] g.) and triethylamine (1.5ml.) are dissolved in ethanol l5 ml.). The reaction mixture is heated atreflux for 5 minutes and chilled. The crude dye is collected on afilter. After one recrystallization from ethanol. the yield of purifieddye is L79 g. (51% yield). m.p. l53l55C.

As used in the structural formulas herein C H is an ethyl group and C His a phenyl group.

The sensitizing effect of the dyes of this invention on negative silverhalide emulsions is illustrated by testing the dyes in a sulfur and goldsensitized. cubic-grained gelatino-silver-bromoiodide emulsioncontaining 2.5 mole percent iodide. The dyes. dissolved in suitablesolvents. are added to separate portions of the emulsion at theconcentrations indicated in Table l and the emulsions are coated at acoverage of lUt) mg. of silver per square foot and 694 mg. of gelatinper square foot on a cellulose acetate film support. A sample of eachcoating is exposed to a tungsten light source in a sensitometer througha wedge spectrograph and through a continuous step wedge using a Wrattenl6 filter (minus blue). Samples are also exposed to the mercury 365 nm.emission line with a mercury lamp through a Wratten 18A filter. Thecoatings are processed six minutes at about 18C. in a x-ray developingsolution such as Kodak D-l9b, fixed. washed and dried. The photo- 2.l-Ethyl-2-( l.2.3.4.5.5u,6.7.8.9- graphic results from these tests areset forth in Table l.decahydrocyclopenta-[c]quinolizin-4-ylidenemethyl)- The speeds are readat 0.3 above fog. The 365 line n hrhq Lldhhi z li i dide, speeds above100 indicate chemical sensitization of the 3. 2-( l.2.3.4.5,Su(6,7,8.9,-Decahydrocyclopentalcldye. The minus blue speedsare compared to the dye of 5quinolizinA-ylidenemethyl)-3-ethyl-5-methoxybenzo- Example 1. thiazoliumperchlorate.

TABLE Dye (one Sens. Sens. Dye of (mg/mole of Rel. Minus Rel. 365 Mzlx.Range Example silver halide) Blue Speed Line Speed Fug (rim) (nm)Control I00 .02 m 490 l 200 I00 :24 .03 555 m 595 2 :00 [4| 224 .04 575m 605 3 300 115 269 .03 560 to (no 4 :00 7x 224 .02 56H m hilt) 400 I 10.02 to 500 h :00 )3 31s .04 560 to 5 m 7 100 R5 2 is .06 565 to 600 a200 m 300 .04 570 to (still 0 400 N12 :00 .10 5x0 to 621) I0 :00 in 200.34 560 to 590 1 2 11 7x 186 .05 560 m 590 l '1 250 ll: (#8 .(16 55" In591) I3 300 174 .u: 500 m 5. 0 14 400 as 224 .04 565 m 620 I5 400 105245 .(lb 580 in m0 m 400 H5 234 .06 570 10 m0 This invention has beendescribed in detail with ref- 4. 2(2.3,4,4a,5,6 7.8,9.lO-Decahydro-lH-benzole1- erence to particular embodiments thereof, but it will bequinolizimo-ylidenemethyl )-3-ethylbenzothiazolium understood thatvariations and modifications can be efiodide. fected within the spiritand scope of the invention as 5.2-(2,3,4.4u.5.6,7,8.9IO-Decahydro-lHbenzo[e]- described hereinabove andas defined in the appended mquinolizin-o-ylidenemethyl)-l-ethylnapthol1.2- claims. d]thiazoliumiodide.

I claim: 6. 5-(2,3,4,4a.5.6.7.8.9,lO-Decahydro-lH-benzo[e] I. A cyanineor merocyanine dye selected from thosequinolizin-o-ylidene)-3-ethylrhodanine. having the formulas 7. A dyeselected from the group consisting of cu n2\u/ e 2 r 2 l cu c CH ofL\D1l/ c 2 wherein m. n, p and each has a value of O or I; r and 3. h l2 2,3,4,5,5a,6,7,8,9-

1; each are 0. l. 2 or 3; L represents a methine group;decahydrocyclopentalc]-quinolizin-4- Z represents the nonmetallic atomsnecessary to comyljdenemcthy])benzothiazolium iodide;

plete a heterocyclic nucleus selected from the group 5-(|,2 3 4 5,56,7,8 9-

consisting of benzothiazole. naphthothiazole.thionaphdecahydrocyclopenta[clquinolizin-4-ylidene )-3- theno-7', 6.4.5-thiazole, oxazole. benzoxazole. naphrh l h d i thoxazole.selenazole. naphthoselenazole. thiazoline. 4 1 2 3 4 5.5 6,7,3,9

-q q l'lsoquinolinfl decahydrocyclopentalclquinolizin-4-ylidene)-3-dialkylindolenine. 2-pyridine. 4-pyridine, imidazolc.methyl-l-phenyl-2-pyrazolin-5-one;

benzimidazole. naphthimidazole and lepidine; R, rep3-ethyl-2-(2,3,3u,4.5.6.7,8-octahydro-lH- rcscnts lower alkyl,carboxyalkyl, sulfoalkyl.hydroxycyclopenta[e]-indolizin-S-ylidenemethyl)benzoalkyl, alkoxyalkyl,sulfoalkoxyalkyl and phenyl; A repthiazolium iodide;

atoms necessary to complete a heterocyclic nucleus seyelqenta[el-indolizin-S-ylidene)rhodanine; lectcd from the group consistingof Z-pyrazolin-S-one. 2-(2.3.4.4a,5,6.7.8.9,lU-decahydro-l H-indandione. 2.4.6-triketo-hexahydropyrimidine. 2.6-benzolclquinolizin-o-ylidenemethyl)-3-ethylnapdiketo-4-thiohexahydropyrimidine.rhodanine. hydanthol2.3-d]thiazolium fluoborate;

loin and thiohydantoin. l-ethyl-2-(2.3.3u 4,5.6.7.8-octahydro-l H-

1. A CYANINE OR MEROCYANINE DYE SELECTED FROM THE THOSE HAVING THEFORMULAS 2.1-Ethyl-2-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta-(c)quinolizin-4-ylidenemethyl)naphtho(1,2-d)thiazolium iodide. 3.2-(1,2,3,4,5,5a,6,7,8,9,-Decahydrocyclopenta(c)-quinolizin-4-ylidenemethyl)-3-ethyl-5-methoxybenzothiazolium perchlorate. 4.2(2,3,4,4a,5,6,7,8,9,10-Decahydro-1H-benzo(e)-quinolizin-6-ylidenemethyl)-3-ethylbenzothiazolium iodide. 5.2-(2,3,4,4a,5,6,7,8,910-Decahydro-1H-benzo(e)-quinolizin-6-ylidenemethyl)-1-ethylnaptho(1,2-d)thiazolium iodide. 6.5-(2,3,4,4a,5,6,7,8,9,10-Decahydro-1H-benzo(e)-quinolizin-6-ylidene)-3-ethylrhodanine.
 7. A dye selected from the group consisting of3-ethyl-2-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta(c)-quinolizin-4-ylidenemethyl)benzothiazolium iodide;5-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta(c)quinolizin-4-ylidene)-3-ethylrhodanine;4-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta(c)quinolizin-4-ylidene)-3-methyl-1-phenyl-2-pyrazolin-5-one;3-ethyl-2-(2,3,3a,4,5,6,7,8-octahydro-1H-cyclopenta(e)-indolizin-5-ylidenemethyl)benzothiazolium iodide;3-ethyl-5-(2,3,3a,4,5,6,7,8,-octahydro-1H-cyclopenta(e)-indolizin-5-ylidene)rhodanine;2-(2,3,4,4a,5,6,7,8,9,10-decahydro-1H-benzo(c)quinolizin-6-ylidenemethyl)-3-ethylnaptho(2,3-d)thiazolium fluoborate;1-ethyl-2-(2,3,3a,4,5,6,7,8-octahydro-1H-cyclopenta(e)-indolizin-5-ylidenemethyl)naphtho(1,2-d)thiazolium iodide;3-ethyl-2-(2,3,3a,4,5,6,7,8-octahydro-1H-cyclopenta(3)-indolizin-5-ylidenemethyl)benzoselenazolium perchlorate;2-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta(equinolizin4-ylidenemethyl)-3-ethylbenzoselenazolium iodide;5-(1,2,3,4,5,5a,6,7,8,9-decahydrocyclopenta(3)quinolizin-4-ylidene)-3-(3-(3-pyrrolin-1-yl)propyl)rhodanine; and 2-(1,2,3,4,5a,6,7,8,9-decahydrocyclopenta(equinolizin-4-ylidenemethyl-3-methylthiazolium perchlorate.